Float finish machine

ABSTRACT

A float finish machine includes a rotor with a disk supporting a set of trowel blades, accommodated in corresponding radial slots, that are angularly adjustable with respect to the rotor about axes that are substantially parallel to the floor. The machine includes an engine and a speed reducer having an output shaft with a sliding collar positioned thereon. An idle spacing element, having a hub that is ensheathed by a sleeve, and that is rotatably coupled with the shaft through the sliding collar, has a diameter greater than the disk and is positioned on the shaft to freely rotate about the axis of the shaft. The sleeve operates in conjunction with a device for setting the angular position of the trowel blades.

The invention concerns a machine for floating floors, that is to say, anassemblage of devices by means of which to effect an automatic smoothingaction on extensive flat surfaces consisting in a layer of concrete ormortar, not yet fully dried; once hardened, such surfaces will providefloors in premises destined for industrial or commercial activity, forexample, or in public or private buildings generally.

The prior of art comprises float finish machines comprising a rotor, ora pair of rotors each equipped with a set of adjustable radial trowelblades cantilevered from a crosswise supporting member driven inrotation about its own vertical axis by an engine and speed reducer.

The German document DE-A-2 502 902, for instance, discloses a floatfinish machine for floating floors, comprising a rotor consisting of adisk, disposed sustantially parallel to the floor, the disc beingprovided with radial slots each accommodating a trowel blade, eachtrowel blade being angularly adjustable about an axis disposedsustantially parallel to the floor, the disc being coupled with a shafthaving its axis disposed substantially perpendicular to the floor. Thisdocument forms the basis for the preamble of the independent claim. Onenotable problem experienced with such machines is that of finishing theareas of the floor adjacent to the walls; this is due principally to thelarge outer diameter of the rotors, typically around one meter and evenmore, which dictates that the crosswise supporting member must maintaina stable horizontal position in order to ensure that its radial arms areprotected from damaging vibrations and excessive shock loads. Suchmachines are therefore unsuitable for finishing the border areas offloors, albeit only slightly uneven or sloping, with the result thatrecourse must be made to the more costly operation of floating by hand.

It often happens, moreover, particularly with single rotor machines,that in an attempt to finish the border areas of a floor exhibiting ashallow depression, the operator will attempt to tilt the vertical axisof the rotor toward the wall; this results in excessive stress beingplaced on the arms of the crosswise supporting member and uneven wear onthe mechanical components of the machine, not to mention damage to theareas of the wall against which the frame of the machine is caused tochafe.

The prior art thus stands in need of considerable improvement, in viewof a possible elimination of the drawbacks mentioned above.

The object of the invention is to provide a float finish machine forfloating floors of cement mortar or other suitable cement compound forindustrial premises and public or private buildings, which is notaffected by vibrations and/or heavy mechanical stresses on the rotorassembly and is suitable in particular for finishing the borders of afloor, even when the floor exhibits slightly concave or sloping areas;moreover, such a machine should not cause damages to the walls duringoperation and must also be functional, efficient and inexpensive.

The float finish machine according to the invention comprises a rotorconsisting of a disk, disposed sustantially parallel to the floor, thedisc being provided with radial slots each accommodating a trowel blade,each trowel blade being angularly adjustable about an axis disposedsustantially parallel to the floor, the disc being coupled with a shafthaving its axis disposed substantially perpendicular to the floorwherein an idle spacing element having an outer diameter greater thanthe outer diameter of the disk is disposed on the shaft.

The profile of each radial slot is advantageously rectangular with thelonger sides parallel to a radial direction; the respective trowelblade, having an outline corresponding to the profile of the slot, isrigidly connected to a shaft rotatably supported to the shorter sides ofthe slot in an intermediate position.

The disk is coupled by means of a central flange to vertically disposedshaft, driven by an engine through a speed reducer, an axially slidablecylindrical collar being coupled to said vertical disposed shaft in aposition between said speed reducer and said central flange, the top endof said slidable cylindrical collar being coupled to an outer coaxialsleeve in such a way the sleeve is allowed to rotate, but is preventedfrom sliding axially, with respect to the collar, said sleeve exhibitingan annular projection engageable from above by the forked end of aforked lever designed to adjust the angular position of the trowelblades by displacing axially the sliding collar and the coaxial sleeve,the other end of the forked lever being hinged to a bottom end of a tierod, said tie rod being inclined with respect to a vertical axis andbeing movable along its own axis.

The bottom end of the sliding collar is equipped with a further annularprojection designed to transmit downward uniformly to the top ends of aset of crank levers a thrust applied to the forked lever, each cranklever being secured to the radially innermost end of a shaft supportinga trowel blade.

The machine also comprises a idle spacing element having a hub rotatablycoupled to the outer surface of the sliding collar and interposedbetween said outer surface and the innner surface of the outer coaxialsleeve, the outer diameter of the spacing element being greater than theouter diameter of the disk supporting the trowel blades so as to preventcontact between the disk and the walls of the room when the machinesworks the border areas of a floor.

The advantages afforded by the present invention are: markedly higherquality of the float finish, especially over slightly uneven or slopingfloor areas near the walls, said higher quality being achieved mainly byvirtue of the reduced vibration to which trowel blades are subjectedwhen supported at both ends; reduced mechanical stresses on the rotor;preventing damages caused by impacts of the frame of the machine againstthe walls of the room where the floor is laid; uniform wear onmechanical components; reasonable cost.

Some preferred embodiments of the invention are illustrated, strictly byway of example, in the seven accompanying sheets of drawings, in which:

FIG. 1 is a side elevation, interrupted and partly cutaway, of a floatfinish machine according to the invention;

FIG. 2 is a section through II--II in FIG. 1;

FIG. 3 is a longitudinal section through III--III in FIG. 2, showing themachine only in part and on a larger scale;

FIG. 4 is a section through IV--IV in FIG. 2, showing the machine onlyin part and on a larger scale;

FIG. 5 is a partial and interrupted side elevation of a device designedto adjust the angular position of the trowel blades, shown partly insection, and on a larger scale;

FIG. 6 is a cross section through VI--VI in FIG. 5;

FIG. 7 is a partial, interrupted longitudinal section through VII--VIIin FIG. 2, illustrating an embodiment of the machine equipped with aroughing tool;

FIG. 8 is a section through VIII--VIII in FIG. 7, seen on a largerscale;

FIG. 9 is a section as in FIG. 2, which illustrates an alternativemethod of fitting a roughing toll;

FIG. 10 is a section as in FIG. 7, also illustrating the alternativemethod of fitting a roughing tool;

FIG. 11 is a section through XI--XI in FIG. 10.

In the drawings, 1 denotes a horizontal disk supporting a plurality ofradially disposed trowel blades 2, each angularly adjustable, the diskbeing carried by a flange 3 keyed to a vertical shaft 4 coupled to anddriven by a speed reducer 5; the speed reducer is driven by a belt drivecomprising a driven pulley 6 connected to the input shaft of the speedreducer, a belt 7 and a driving pulley 8 afforded by a clutch assembly 9with centrifugal weights keyed to the crankshaft 10 of an engine 11mounted above. 12 denotes the fuel tank of the engine 11, and 13 abottom flange of the engine crankcase, which is secured to the top face13a of the speed reducer 5 beneath.

13b denotes a pair of shafts extending upward and back from the rearface of the speed reducer casing, the top ends of which are joined to ahandlebar (not illustrated) by which the machine is manoeuvred, and towhich the main operating controls are mounted.

14 denotes a device for setting the angular position of the trowelblades 2, comprising an angled tie rod 15 having a topmost end pivotablyconnected to an adjustment screw 16 rotatable in such a way as to varythe longitudinal position of the rod 15 and thus vary the angle betweenthe blades 2 and the surface of the floor. The screw 16 turns in athread afforded by a cross member 16a interconnecting the angled shafts13b. The bottom end of the tie rod 15 is pivotably connected to the rearend of an oscillating lever 17 fashioned with a forked forward end, saidforked end being designed to apply a pressure to an annular projection18 afforded by the bottom end of a sleeve 19 coaxially mounted on therotor shaft 4 and rotatably coupled with a coaxial internal slidingcollar 21 slidably coupled with the rotor shaft.

22 denotes a further annular projection extending radially from thebottom of the sliding collar 21, said annular projection being designedto transmit and distribute a thrust exerted by the forked forward end ofthe rocking lever 17 to the top ends of a plurality of crank levers 23each keyed to a radially innermost end 23a of a respective shaft 23bsupporting a respective trowel blade 2, said blade being fastened to aflat bottom face 23c of a shaft 23b.

24 denotes an idle spacing element having a peripheral surface coatedadvantageously with a resilient shock-absorbent material and a hub 24ainterposed between the inner surface of the sleeve 19 and the outersurface of the sliding collar 21 and rotatably coupled to the slidingcollar.

The outer diameter of the idle spacing element 24 is greater than theouter diameter of the disk 1 carrying the trowel blades 2, so as toensure that the peripheral surface of the disk is prevented fromentering into contact with the walls at the sides the floor.

25 denotes a handle secured to the forwardmost surface of the speedreducer 5, used for the purpose of lifting and transporting the machine,and 26 denotes one of a pair of lugs extending downward from the sidesof the speed reducer 5, to which the forked arms of the oscillatinglever 17 are hinged at an intermediate position.

27 denotes a slot of a formation of radial through slots (FIG. 2)carrying the trowel blades 2, each appearing rectangular when viewed inplan, said slots being advantageously spaced apart at an angulardistance for example of between 45° and 90° approximately.

Each radial slot 27 has a length advantageously greater than the half ofthe radius of the disk 1, and a width sufficient to admit andaccommodate the articulating movement of a forward edge 28 of acorresponding trowel blade 2, the forward edge being angled slightlyupward so as not to catch in the surface of the floor.

29 denotes the bearings (FIG. 4) rotatably supporting the ends of eachtrowel blade 2, said bearings being secured to the top face of the diskadjacent to the shorter sides of each radial slot 27 and destined toaccommodate the radially inner and outer ends 23a and 30 of a shaft 23b.

31 denotes a plurality of slots (FIG. 8) located in regular formationaround the periphery of the disk, at an angular distance of 120° forexample, designed to receive a corresponding plurality of angled catchpin elements 32 projecting rearwards with respect to the direction ofrotation of the disk 1 and projecting upward from the top surface of aroughing tool 33, said roughing tool being shaped as a disk affordingand being fitted to the disk 1 from beneath.

34 denotes a central cavity in in the working surface of the roughingtool designed to prevent the portions of the tool revolving at aperipheral velocity insufficient for roughing purposes from enteringinto contact with the floor: preferably, the cavity 34 has radius lessthan the radius of the disk 1.

35 denotes a plurality of slots (FIG. 9) located in regular formationaround the periphery of the disk at an angular distance of 120° forexample, designed to receive a corresponding plurality of substantiallycylindrical retaining catch pin elements 36 projecting upward from thetop surface of the roughing tool 33, each catch pin element exhibitingan intermediate portion 37 of reduced diameter. Each slot 35 comprises afirst stretch 38 of width sufficient to accommodate the intermediateportion 37 of the retaining element 36 with a degree of clearance,followed in the direction of rotation of the disk 1 by a second stretch39 of greater width able to accommodate the cylindrical element 36 inits entirety, likewise with a degree of clearance.

Operation of the machine is as follows: having selected the prescribedangle of contact between the bottom face of the trowel blades and thesurface of the floor, by turning the adjustment screw 16 so as to raiseor lower the tie rod 15 and thus determine the required angular positionof the oscillating lever 17 and the corresponding axial position of thesliding collar 21, the engine 11 is started, thereby activating theclutch 9, the belt and pulley drive 6, 7, 8 and the speed reducer 5, andultimately the rotor shaft 4 and the disk 1 with the trowel blades. Whenpassing the machine over the border areas of the floor, the outermostedge of the disk 1 is prevented from rubbing against the skirting wallsby the idle spacing element 24. To advantage, if the machine is fittedwith a roughing tool 33, the outer diameter of the idle spacing element24 will be greater than the outer diameter of the tool.

I claim:
 1. A float finish machine for floating floors, comprising arotor including a disk, disposed substantially parallel to the floor,the disk being provided with radial slots each accommodating a trowelblade, each trowel blade being angularly adjustable with respect to aplane of the rotor about an axis disposed substantially parallel to thefloor, the disk being coupled with a shaft having its axis disposedsubstantially perpendicular to the floor, with an idle spacing element,having a hub coupled rotatably with the rotor, said idle spacing elementhaving an outer diameter greater than the outer diameter of the diskpositioned upon the shaft, being free to rotate about the axis of theshaft.
 2. A machine as in claim 1, wherein each blade is fixed to theflat bottom face of a respective shaft disposed substantially parallelto the floor, said respective shaft having each end rotatably supportedby the disk at an intermediate position on a shorter side of the slots.3. A machine as in claim 2, wherein the shaft is provided with drivingmeans and with a sliding collar disposed with an annular projection. 4.A float finish machine for floating floors, comprising a rotor includinga disk, disposed substantially parallel to the floor, the disk havingradial slots each accommodating a trowel blade, each trowel blade beingangularly adjustable with respect to a plane of the rotor, each trowelblade being fixed to the flat bottom face of a respective shaft about anaxis disposed substantially parallel to the floor, said respective shafthaving each end rotatably supported by the disk at an intermediateposition on a shorter side of the slots, the disk being coupled with ashaft having its axis disposed substantially perpendicular to the floor,with an idle spacing element having an outer diameter greater than theouter diameter of the disk positioned along the shaft parallel to thefloor, said idle spacing element being free to rotate about the axis ofthe shaft, the shaft is provided with driving means and with a slidingcollar disposed with an annular projection, said sliding collar isrotatably coupled with said idle spacing element, said idle spacingelement having a hub ensheathed by a sleeve capable of axial movement asone with the sliding collar while rotatable in relation thereto, saidsleeve affords an annular projection co-operating with a device forsetting the angular position of the trowel blades, said device forsetting the angular position of the trowel blades comprises a forkedoscillating lever engaging said angular projection, said forkedoscillating lever being pivotably connected to one end of a tie rodhaving a second end pivotably connected to an adjustment screw.
 5. Amachine as claimed in claim 3, wherein said sliding collar is rotatablycoupled with said idle spacing element, said hub of said idle spacingelement ensheathed by a sleeve capable of axial movement as one with thesliding collar while rotatable in relation thereto.
 6. A machine as inclaim 5, wherein said sleeve affords an annular projection co-operatingwith a device for setting the angular position of the trowel blades. 7.A machine as in claim 6, wherein said device for setting the angularposition of the trowel blades comprises a forked oscillating leverengaging said annular projection, said forked oscillating lever beingpivotably connected to one end of a tie rod having a second endpivotably connected to an adjustment screw.
 8. A machine as in claim 6,wherein the annular projection of said sliding collar engages aplurality of crank levers, each crank lever being keyed to one end of arespective horizontally disposed shaft.
 9. A machine as in claim 1,wherein said disk is provided with a flat roughing tool exhibiting aprofile matched substantially to that of the disk when viewed in plan,the flat roughing tool disposed with a central cavity.
 10. A machine asin claim 9, wherein the flat roughing tool is provided with a set ofcatch pin elements engaging corresponding slots of the disk.
 11. Amachine as in claim 10, wherein, with the exception of the slots forengaging the roughing tool, the disc has no apertures between the radialslots.
 12. A machine as in claim 10, wherein the catch pin elements areangled rearwardly with respect to the direction of rotation of the disk.13. A machine as in claim 10, wherein the catch pin elements aresubstantially cylindrical in shape and are provided with an intermediateportion of reduced diameter.
 14. A machine as in claim 13, wherein eachslot comprises a first stretch having a width greater than the diameterof intermediate portion of the catch pin element but less than thediameter of the catch pin element, said first stretch being followed inthe direction of rotation of the disk by a second stretch having a widthgreater than the diameter of the catch pin element degree of clearance.15. A machine as in claim 1, wherein the profile of the single trowelblade, viewed in cross section, appears substantially laminar with anupwardly angled forward edge.